From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A89C7FC5926 for ; Thu, 26 Feb 2026 10:51:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:From:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vuf9p+K+CpXtf4kZkaIKXjdKIsukISTMXyjOai+xhDs=; b=EbejWORy2GmTgeTLihnXNJIUHu SRw+863tx3IYsI7NmgVZ/46k+iIwr3kU9aYFlh6hdWh7g0S2uT/b8kITKi/O3BOUOarUv13iOupQb AcRzukv2BST7Eor6xP5apvnCwZsbY3xGb9/yQrr7m2erOZnSxF6EBWaoafx2fVrJ9KJ+Sf3QtxVeT I/Oke2KIUzK6W+lm54n9ZWfG3FbIhGbhLdK3C7hMmzjMHNruY3Yj6s2+ExZmKtAh2L8gIEgo8IHRo d9el4wXq4cwRAPoo9oEUjDiVZuDZ7y+NaN2JC3MzzU+iqxRiWLIYP2zLq3S9KcLKKvAFc4OJHHe5f ckcy2Kbg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vvYyD-00000005xqa-1IE9; Thu, 26 Feb 2026 10:51:49 +0000 Received: from bali.collaboradmins.com ([148.251.105.195]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vvYyB-00000005xq3-1jWx; Thu, 26 Feb 2026 10:51:48 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1772103104; bh=IkJdKD7faa2UuFj9IHFkVko8rvI1zt0tw5f/fUIjArE=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=YGmER0kqMduk83TZ1QAJY/NXqU+hh+kbXJhqkRW/mnZQAmjrBJ04xrH+5wLktOZbt eWm3qnQ5dmtSOdUwgdfefUxO4RmYV9TX21epX4xPPkdk2Lgr/P+p4kQa8zUgCsCgkn gcnWJjcPor7ZwVQrW8hzhNsiAWHU393WOLc9khrZq8U23qDIy7xhVgDjxv818Lii3A RMcoG2qoUYaaw2us5sXxd9HbLvBxqwbfMdVhpV49o3H8OqaEiyAmwn2c6a7VdT+TsX Q8yDzOZu6Tatl/9AHh5YLDLEUCtFj9SG2tNFsMaxyORcgfvjCOW++RyaP64BMYQxmT uR5EeNVeMuZSA== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 2276E17E03E5; Thu, 26 Feb 2026 11:51:44 +0100 (CET) Message-ID: <67acc82d-e145-4f98-88b2-d30cc73f73a0@collabora.com> Date: Thu, 26 Feb 2026 11:51:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/11] Plane Color Pipeline support for MediaTek From: AngeloGioacchino Del Regno To: =?UTF-8?B?Q0sgSHUgKOiDoeS/iuWFiSk=?= , "pekka.paalanen@collabora.com" , Nicolas Prado , "harry.wentland@amd.com" Cc: "wiagn233@outlook.com" , "tzimmermann@suse.de" , "simona@ffwll.ch" , "mripard@kernel.org" , Daniel Stone , "linux-mediatek@lists.infradead.org" , "maarten.lankhorst@linux.intel.com" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "chunkuang.hu@kernel.org" , "kernel@collabora.com" , Ariel D'Alessandro , "p.zabel@pengutronix.de" , "xaver.hugl@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "airlied@gmail.com" , "matthias.bgg@gmail.com" References: <20251223-mtk-ovl-pre-blend-colorops-v1-0-0cb99bd0ab33@collabora.com> <20260206110901.660cf712@eldfell> <5963bca37996fa054ad75d4e5017d9c7e5158e9f.camel@collabora.com> <3efaa7ec40c68f0d463da00c3a57474a40d4fdae.camel@mediatek.com> <2e241629-2526-41c5-92fd-a0a0ec3ffc4e@collabora.com> Content-Language: en-US In-Reply-To: <2e241629-2526-41c5-92fd-a0a0ec3ffc4e@collabora.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260226_025147_598780_3AAFBCE2 X-CRM114-Status: GOOD ( 27.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Il 26/02/26 11:26, AngeloGioacchino Del Regno ha scritto: > Il 26/02/26 07:24, CK Hu (胡俊光) ha scritto: >> On Fri, 2026-02-06 at 08:28 -0500, Nícolas F. R. A. Prado wrote: >>> On Fri, 2026-02-06 at 11:09 +0200, Pekka Paalanen wrote: >>>> On Fri, 2 Jan 2026 13:40:21 -0500 >>>> Harry Wentland wrote: >>>> >>>>> On 2026-01-01 07:37, Shengyu Qu wrote: >>>>>> >>>>>> >>>>>> 在 2025/12/30 02:53, Shengyu Qu 写道: >>>>>>> >>>>>>> >>>>>>> 在 2025/12/24 3:44, NÃ colas F. R. A. Prado 写道: >>>> >>>>>>>> Given the lack of support for writeback connectors on the >>>>>>>> MediaTek KMS driver, combined with limited hardware >>>>>>>> documentation, I haven't been able to verify the correctness >>>>>>>> of >>>>>>>> each curve, only that they were visually sane (gamma curves >>>>>>>> made >>>>>>>> the image on the display brighter, while inverse gamma made >>>>>>>> it >>>>>>>> darker). >>>>>>> >>>>>>> Hmmm I don't think this is acceptable. sRGB/scRGB has two >>>>>>> transfer >>>>>>> functions mentioned in original specification[1]. To keep color >>>>>>> accuracy, we need someone from mediatek confirm whether this is >>>>>>> piece- wise or pure power 2.2 transfer function, this is >>>>>>> already >>>>>>> done in original amdgpu color pipeline series, sRGB means >>>>>>> piece-wise while also dedicated power 2.2 function exists. >>>>> >>>>> Not sure what you mean with this not being acceptable. This is >>>>> about >>>>> enabling HW support for this functionality. Not every HW has >>>>> writeback for testing. At some point you'll have to trust the >>>>> driver >>>>> devs if you're going to use functionality of the driver. We're not >>>>> always going to get everything perfect, but if that's really such a >>>>> worry you can always use shaders to do precisely what you want. >>>>> >>>> >>>> Hi Harry, >>>> >>>> yes, but I understood that in this case, the hardware documentation >>>> available is so vague that it's impossible to say what it will >>>> actually >>>> do. There are no formulas given or referenced in the documentation, >>>> are >>>> there, Nícolas? >>> >>> No formulas at all, the only documentation I had available for the >>> curves was the register definition, which simply lists the possible >>> values: SCRGB, BT709, BT2020, HLG. >> >> Hi, Nicolas: >> >> In [1], it shows OVL could output data to WDMA which could write data into DRAM. >> Its control is similar to RDMA. RDMA read data from DRAM and WDMA write data into >> DRAM. >> Do you have interest to implement WDMA? > > I wrote a WDMA driver a long ago, but I couldn't get it to work (though, I admit I > didn't try hard to actually get it working).... if you want to take a look to check > if anything obvious is missing, the driver is here: > > https://gitlab.collabora.com/mediatek/aiot/linux/-/blob/mediatek-dev/drivers/gpu/ > drm/mediatek/mtk_disp_wdma.c?ref_type=heads > > The driver I wrote was supposed to work on MT8781 Helio G99 (for a personal project Eh, sorry for the double email, I was meaning MT6789 Helio G99 - just to be extremely clear, though that wasn't much important (given that the WDMA IP is anyway practically the same between the two..). > as in upstreaming of the Xiaomi Poco M5 smartphone) and on MT8195 as a PoC. > I did test both platforms and this driver didn't work on both... not sure if that > was because I misconfigured the MMSYS routing (on both) or if there's any actual > issue with the driver I wrote. > > Again, didn't invest much time on this, anyway, so some obvious issue might be > present. > > Cheers, > Angelo > >> This is just a suggestion. >> I could accept we believe what document say first and wait for someone to verify it. >> >> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/ >> drivers/soc/mediatek/mt8195-mmsys.h?h=v7.0-rc1#n8 >> >> Regards, >> CK >> >>> >> > >